Search disappears on iPhone

Hi,

I have Primary Menu/ Drop Down selected and it works perfectly on PC & Tablet

But if I look at my site on my phone the menu bar has been replaced by the ‘MENU’ word and you click it to display the menu categories on the site but the Search bar is now missing ?

I replicated this on the PC by altering the window size to check for resolution on different size screens. So I decreased the size of my window until the menu bar disappears and defaults to the words ‘MENU’.

Then when I open the ‘MENU’ drop down after clicking it – the search icon has disappeared completely ?

Any ideas ?

Thanks